LAYING OUT A DRAIN OR SYSTEM 



125 



the fore-sight reading 

 was taken. If the 

 proper subtractions are 

 made in Table XIV and 

 the elevations properly 

 introduced in the 

 column for elevations, 

 it will be observed that 

 the elevations of the 

 several stakes are iden- 

 tical with those for the 

 same stakes as recorded 

 in Table XV. 



168. Preliminaries 

 to establishing grade of 

 ditch, cut, and the like. 

 We are now ready to 

 establish the depth of 

 the ditch at certain 

 points, and to determine 

 the fall. To help in 

 these computations, a 

 diagram or profile, sim- 

 ilar to that shown in 

 Fig. 48, should be used. 

 This diagram is drawn 

 upon ordinary profile 

 paper. Figure 49 shows 

 how the same work 

 may be accomplished 

 with a crude diagram 

 drawn upon letter paper 

 or rough note paper. 



N K 

 II 



